Chemical composition: Cu2CO3(OH)3
Malachite is a stone that is varying shades of green, and is used as a decorative stone, since it is easily cut and polished. Though its softness limits its use as a gemstone, its beauty is hard to resist. Popular as a decorative stone in Czarist Russia, it was used to make the columns of St. Isaac’s Cathedral in Leningrad. Malachite rarely occurs in prismatic crystals, and is a well know secondary copper mineral, meaning that it is formed when copper minerals are altered by other chemicals.
This green stone occurs when carbonated water interacts with copper minerals, or when a solution of copper interacts with limestone. Crystals sometimes form as needles that fan out from the rock in which they are embedded. More often, malachite forms as a mass with concentric bands of light and dark green. Malachite is usually found with azurite, a blue secondary mineral of copper. Sometimes a mineral sample can have alternating bands of green malachite and blue azurite.
This diverse mineral can be found in Russia, Zaire, Australia, and Namibia. Though a bit closer to home, specimens have been found in the copper mines of Arizona, California, Nevada, Utah, Pennsylvania, and Tennessee.
Sanding Malachite can cause it to give off a poisonous dust. So, better watch out when you’re working with this mineral!